U.S. patent application number 10/554794 was filed with the patent office on 2007-07-05 for optical switching using optical fiber connector.
Invention is credited to Andrew Nicholas Dames, Michael Francis Grant.
Application Number | 20070154138 10/554794 |
Document ID | / |
Family ID | 32408044 |
Filed Date | 2007-07-05 |
United States Patent
Application |
20070154138 |
Kind Code |
A1 |
Dames; Andrew Nicholas ; et
al. |
July 5, 2007 |
Optical switching using optical fiber connector
Abstract
An optical switching device, comprises an optical switch and an
optical connector receiving means mateable with a connector., means
for effectuating switching by engaging a connector in said
receiving means, characterised in that said switching effectuating
means acts or is acted upon once a connector is sufficiently
engaged in the receiving means for optical communication with the
connector to occur.
Inventors: |
Dames; Andrew Nicholas;
(Cambridge, GB) ; Grant; Michael Francis; (Herts,
GB) |
Correspondence
Address: |
WORKMAN NYDEGGER;(F/K/A WORKMAN NYDEGGER & SEELEY)
60 EAST SOUTH TEMPLE
1000 EAGLE GATE TOWER
SALT LAKE CITY
UT
84111
US
|
Family ID: |
32408044 |
Appl. No.: |
10/554794 |
Filed: |
April 30, 2004 |
PCT Filed: |
April 30, 2004 |
PCT NO: |
PCT/GB04/01916 |
371 Date: |
January 17, 2007 |
Current U.S.
Class: |
385/19 ;
385/18 |
Current CPC
Class: |
G02B 6/3524 20130101;
G02B 6/3514 20130101; G02B 6/3564 20130101; G02B 6/357 20130101;
G02B 6/3546 20130101; G02B 6/3572 20130101; G02B 6/358 20130101;
G02B 6/3574 20130101 |
Class at
Publication: |
385/019 ;
385/018 |
International
Class: |
G02B 6/26 20060101
G02B006/26; G02B 6/42 20060101 G02B006/42 |
Foreign Application Data
Date |
Code |
Application Number |
Apr 30, 2003 |
GB |
0309898.5 |
Claims
1. An optical switching device, comprising an optical switch and an
optical connector receiving means mateable with a connector, means
for effectuating switching by engaging a connector in said
receiving means, wherein said switching effectuating means acts or
is acted upon once a connector is sufficiently engaged in the
receiving means for optical communication with the connector to
occur.
2. Device according to claim 1, wherein the connector receiving
means is so configured so that when a connector is mated with the
connector receiving means, it allows a connector to be locked in
its operative position by a snap action and means are provided to
allow the connector receiving means to cause switching as a result
of the snap action.
3. Device according to claim 2, wherein the device is adapted so
that the switching is caused by a connector lever.
4. Device according to claim 1, wherein the connector receiving
means is a duplex receiving means with a single lever receiving
portion which allows a duplex connector lever to cause
switching.
5. Device according to claim 1, wherein the means for effectuating
switching incorporate a reflecting or refracting element mounted on
a flexure plate which is configured to return said elements when
the connector is removed from the receiving means.
6. Device according to claim 1, wherein the means for effectuating
switching operate by the completion of an electrical circuit when
the connector is pushed fully home.
7. Device according to claim 1, wherein the means for effectuating
switching operate by magnetic means.
8. A device for extending the functionality of an optical network
by the addition of an optical element, comprising an optical
switching device as claimed in claim 1.
9. An optical switching device, comprising an optical switch and an
optical connector receiving means mateable with a connector,
wherein the switching is triggered by an external source which when
applied causes a locking mechanism to lock the connector in the
receiving means.
10. A device according to claim 9, wherein means are provided to
ensure that light is transmitted to the connector only when a
connector is in position in the receiving means.
Description
FIELD OF THE INVENTION
[0001] The invention relates to an optical switching device and a
device for extending the functionality of an optical network
comprising such an optical switching device.
BACKGROUND OF THE INVENTION AND CLOSEST PRIOR ART HNOWN TO THE
APPLICANT
[0002] One of the major problems in designing optical networks is
in the placement of the optical components, such as Optical Add
Drop Multiplexers (OADMs), optical switches, amplifiers, equalisers
and dispersion-compensating elements. Design decisions on the
inclusion and placement of such elements need to accommodate not
only the initial traffic on the network, but also future network
growth, which is often unpredictable. This issue is especially
critical for Metropolitan (or city) networks where cost needs to be
minimised and growth is especially unpredictable.
[0003] The closest prior art to the invention is acknowledged:
[0004] JP040366804A; (Hitachi); [0005] US6463189B1 (Avanex); [0006]
US6430332 (Fibre); [0007] JP020272405A (Fujitsu); [0008] US5179602
(Norcross).
SUMMARY OF THE INVENTION
[0009] In accordance with a first broad independent aspect of the
invention, there is provided an optical switching device comprising
an optical switch and an optical connector receiving means mateable
with a connector, means for effectuating switching by mating a
connector with said receiving means, characterised in that said
switching effectuating means acts or is acted upon once a connector
is sufficiently mated with the receiving means for optical
communication with the connector to occur.
[0010] One application of such an optical switching device is in
the field of optical networks, where it may be desired to retrofit
an optical element into the network. In this case the present
invention provides for a device for extending the functionality of
an optical network by the addition of an optical element, the
device comprising an optical switching device as just recited, the
connector being connected to said optical element.
[0011] The advantage of using such a hybrid switch-connector
structure is that standard equipment installation practices
developed for use with optical connectors and passive devices can
be used. Installation personnel simply clean the connector ends and
plug the optical element into the network. There is no procedural
discontinuity between the actions of plugging the optical element
into the network and activating the switch to reroute the traffic
through the optical element.
[0012] The hybrid switch-connector structure in question is also
particularly advantageous because it is not dependent upon the
velocity with which a user must insert the connector to the
receiving means. Once the connector is in an appropriate position
switching occurs immediately without abnormal effort to the user.
This marks a radical departure from the teaching of prior art
documents such as Fujitsu (referenced above), where the input or
output ports of the switch are displaced in a manner directly
dependent on the velocity of insertion of the connector and during
the insertion of a connector rather than once secured into
position.
[0013] With careful design, it is possible to have the optical
switching action take place in <10 ms, which is short enough for
the element to be introduced without significantly impacting the
optical traffic in the network.
[0014] In a subsidiary aspect in accordance with the invention's
broadest aspect, the connector receiving means is configured so
that when a connector is mated with the connector receiving means,
it allows a connector to be locked in its operative position by a
snap action and means are provided to allow the connector receiving
means to cause switching as a result of the snap action. This
configuration is particularly advantageous because it may employ a
standard connector to actuate the switching effectuating means in a
rapid and secure manner.
[0015] In a further subsidiary aspect, the device is adapted so
that the switching is caused by a connector lever.
[0016] In a further subsidiary aspect, the connector receiving
means is a duplex receiving means with a single lever receiving
portion which allows a duplex connector lever to cause switching.
This configuration allows enhanced accuracy to be achieved for a
duplex application. It also reduces the number of components
required to receive a single lever duplex connector.
[0017] In a further subsidiary aspect, the means for effectuating
switching incorporate a reflecting or refracting element mounted on
a flexure plate which is configured to return said elements when
the connector is removed from the receiving means. This structure
is particularly advantageous because it achieves high levels of
repeatability with rapid switching without modifying an operator's
connection motion.
[0018] In a further subsidiary aspect, the means for effectuating
switching operate by the completion of an electrical circuit when
the connector is pushed fully home.
[0019] Actuation of the switch may be by electrical, purely
mechanical or purely magnetic means. An advantage of electrical or
purely magnetic actuation is that it simplifies the hermetic
sealing of the switch, thereby protecting it against the
undesirable ingress of foreign matter. A second advantage of the
electrical actuation is that it allows numerous existing
electrically activated switch structures to be used in this hybrid
switch-connector structure. An advantage of purely mechanical or
purely magnetic actuation is that it requires no external source of
power to actuate the switch.
[0020] In a second broad independent aspect, the invention provides
an optical switching device, comprising an optical switch and an
optical connector receiving means mateable with a connector,
characterised in that the switching is triggered by an external
source which when applied causes a locking mechanism to lock the
connector in the receiving means.
[0021] In a subsidiary aspect in accordance with invention's second
broad aspect, means are provided to ensure that light is
transmitted to the connector only when a connector is in position
in the receiving means.
BRIEF DESCRIPTION OF THE DRAWINGS
[0022] FIG. 1 is a schematic diagram illustrating the principle of
the invention;
[0023] FIGS. 2(a), 2(b) and 2(c) are diagrams showing the operation
of an optical switching device in accordance with a first
embodiment of the invention;
[0024] FIG. 3 is a diagram of a second embodiment of an optical
switching device in accordance with the invention;
[0025] FIGS. 4(a) and 4(b) are diagrams showing the operation of an
optical switching device according to the invention in a third
embodiment thereof;
[0026] FIGS. 5(a) and 5(b) illustrate the operation of an optical
switching device in which a variant type of 2.times.2 switch is
employed, and
[0027] FIGS. 6(a) and 6(b) illustrate the operation of an optical
switching device employing a further variant type of 2.times.2
switch;
[0028] FIG. 7 illustrates a schematic perspective view of a further
variant of the invention;
[0029] FIG. 8 shows an end view of a receiving means in accordance
with a further embodiment of the invention;
[0030] FIG. 9 shows a schematic plan view of a further embodiment
of the invention.
[0031] FIG. 10 shows a schematic plan view of a further embodiment
of the invention.
[0032] FIG. 11 shows a schematic plan view of a further embodiment
of the invention.
DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION
[0033] The principle of the invention is illustrated in FIG. 1. In
FIG. 1 an optical switching device comprises an optical switch in
the form of a 2.times.2 switch 10, which is connected on one side
to an existing network 12 and on the other side to one half 14 of
an optical connector 16. In this embodiment, half 14 acts as a
receiving means. The other half 18 of the optical connector 16
(which may be also referred to as a connector) is connected to an
optical element 20, which may be, purely by way of example, an
amplifier, an add-drop multiplexer, and so on.
[0034] In a first mode of operation of the device, the switch 10
with the first connector-half is in-situ inserted in the existing
network 12 and is configured so that the optical signal on port 22
is routed directly through to port 24. Ports 26 and 28 of the
switch are dormant at this stage and are simply connected to the
half 14 of the connector 16 ready for when it is desired to extend
the functionality of the network 12.
[0035] When the time comes to extend the network by the addition of
the optical element 20, the second half 18 of the connector 16 is
mated up with the first half 14 and the action of mating these two
halves together actuates the switch 10 (see broken line 30) so that
the optical signal on port 22 is routed through to port 26, out to
the optical element 20 via the connector halves 14 and 18, back
through the connector halves 18 and 14 and then out through port 24
of the switch to the network. Thus the optical element 20 has been
"retrofitted" into the network.
[0036] The actuation of the switch by the connector-mating action
may take any of a number of forms. One such form, which is purely
mechanical, is shown in FIG. 2(a). In FIG. 2(a) a 2.times.2 switch
40 comprises a switch body 42, which houses at one end a pair of
fiber guides 44, 46. The guides may also operate in conjunction
with respective collimators. At the other end of the body 42 there
is a corresponding pair of fiber guides/collimators 48, 50. Also
attached to the other end of the body 42 is a ferrule 52, which
functions as one half of an optical connector. Also present in the
body is a prism 54, which has two total internal reflection
surfaces 56, 58, and a lever 60 attached to the prism. The prism is
held in the body in a manner such that it can slide, by means of
pressure applied to the lever, downwards so as not to obstruct
optical radiation in the guides. The body 42 has a detent 62 for a
reason to be explained in connection with FIGS. 2(b) and 2(c).
[0037] In the first mode of operation of the switch, the optical
signal entering the optical guide 44 is reflected off of the
surfaces 56 and 58 and back out through the optical guide 46. In a
second mode of operation, when it is desired to upgrade the network
by the addition of an optical element, a second connector half 70
(see FIG. 2(b)) is fitted over the ferrule 52 so that a mating
surface 55 of the second connector half directly abuts the end of
the ferrule 52. In this position two further optical
guides/collimators 72, 74 can carry light which will eventually
exit from or enter the guides 48, 50. The guides 72, 74 are taken
to the optical element 76 via optical fibers.
[0038] Once the two connector halves (or in other words the
receiving means and a connector) are offered up to each other as
shown in FIG. 2(b), a bulkhead 78 is pushed forward so that the
hooked end 80 of a spring-loaded arm 82, which is pivotally
attached to the bulkhead 78, rides over the detent 62 and falls
back down behind the detent (see FIG. 2(c)). In the process the
hooked end 80 depresses the lever 60, thereby pushing the prism 54
down, allowing the optical signals to pass between the guides at
the two ends of the body 42. (The prism is also spring-loaded at
its lower end in order to allow it to regain its original position
once the bulkhead 78 is retracted.) Thus, as explained in
connection with FIG. 1, the optical element is now part of the
network attached to the guides 44, 46.
[0039] A second embodiment of the invention employs an electrical
form of actuation of the 2.times.2 switch. This is shown in FIG. 3,
in which the two connector halves 14, 18 (or in other words a
receiving means and a connector) are associated with additional
electrical switch members 80, 82, respectively. In the realisation
shown in FIG. 3, the switch member 82 consists simply of a fixture
84 having at its end which is to face its opposite number 80 a
small peg 86. The peg 86 fits inside switch member 80, which is
attached to the connector-half 14, and operates a single-pole
switch 88, thereby completing a circuit consisting of wires 90, 92,
a battery or other source of power 94 and an actuation means inside
the 2.times.2 switch 10. This actuation means may take the form of
an electromagnetic actuating device such as a very small solenoid,
which displaces an optical element such as the prism shown in FIGS.
2(a), (b) and (c).
[0040] In practice provision must be made for allowing the
guide-ends in the connector halves to come together before switch
actuation takes place. This will require an arrangement in which
the peg 86 only operates the switch 88 after the connector halves
have fully mated. This may be achieved by arranging for the switch
member 82, for example, to be moveable in an axial direction
relative to connector half 18, while at the same time being
attached thereto. Alternatively, an electrical delay could be
included in the electrical circuit formed by items 94 and 88 shown
in FIG. 3.
[0041] The 2.times.2 switch may be actuated not only mechanically
or electrically, but also by purely magnetic means. An example of
this is shown in FIG. 4. In FIG. 4(a) a 2.times.2 switch 100
comprises a body 102 containing optical guides/collimators 104, 106
at opposite ends, between which is disposed offset from the common
axis of the guides a prism 108, having two reflective sides.
Secured to the prism is a small iron frame 110 having two legs.
112, 114 perpendicular to the guide axis and respective
end-portions 116, 118 parallel to the guide axis. The legs are
provided with cut-outs allowing light to pass through unhindered.
Orientated perpendicularly to the guides 104, 106 are further
guides 130, 132. A first connector-half 117 (or in other words a
receiving means) is attached by some suitable means to the body
102.
[0042] Attached to radially opposite ends of the second
connector-half 124 (or in other words a connector) are two small
permanent magnets 120, 122 orientated magnetically as shown (the
polarities of both magnets may be of sign opposite to that shown in
the figure). The magnets are advantageously sunk into the connector
half itself, e.g. located inside respective bores made in the
connector half, or they may be external to the connector half. In
this embodiment it is necessary to orientate and position the
second connector half accurately with respect to the switch itself,
both from the point of view of enabling a reliable magnet actuation
action and, even more importantly, from the point of view of
ensuring good light transfer from the switch to the guides of the
second connector half. To this end the first connector-half 117 is
accurately positioned with respect to the switch body 102 and it
has a bore 119, which is designed to be a snug fit around the
second connector-half 124. To ensure good alignment between the
guides 130, 132 and the guides 126, 128, the two connector-halves
117, 124 are keyed to each other, e.g. by the provision of an axial
groove in the first connector-half 117 and a corresponding axial
ridge in the second connector-half 124. There may also be a
releasable latching means (not shown) for selectively latching and
unlatching the second connector-half to/from the first once they
are mated together.
[0043] In operation, when the second connector half 124 is
introduced into the first connector-half 117, the frame is
attracted towards the magnets and the prism is displaced downwards,
the end-portions 116, 118 of the frame coming to rest against the
bottom of the body 102 (see FIG. 4(b)). (It should be noted that
the prism will be restrained as regards any lateral movement so
that it maintains the same axial position as far as the guides 104,
106 are concerned). In this position the prism acts to totally
reflect any signals entering/leaving the various guides -see arrows
in FIG. 4(b). In this version of the invention the network
connections are to the guides 104, 106, while the optical element
to be retrofitted to the network is connected to the guides 126,
128 in the second connector half 124.
[0044] Instead of the whole frame 110 being composed of a magnetic
material, only the end-portions 116, 118 may be magnetic, the rest
being made of, e.g., a synthetic material. Furthermore, it is
possible arrange for the frame 110 in FIGS. 4(a) and 4(b) to be,
for example, rectangular in shape, whereby the legs 116, 118 are
replaced by one horizontal member forming one side of a rectangle,
or are still in the form of two legs, but facing inwards instead of
outwards, and to employ either two magnets, as shown in the
figures, or one magnet only, perhaps disposed centrally in the
second connector half.
[0045] An advantage of magnetic actuation is that it allows the
switch to be hermetically sealed, since no direct connection is
made with any internal component of the switch.
[0046] An alternative realisation of the 2.times.2 switch function
is shown in FIG. 5. Here a rectangular (preferably square) prism
140 is held inside a switch body 142 such as to be pivotable about
its centre on an axis perpendicular to the axes of the optical
guides 144, 146, 148 and 150. In the first mode of operation, when
the switch is part of an existing network allowing optical signals
to pass between various parts of the network signals pass from
guide 144 through the prism 140 and out of guide 148. No refraction
of the optical signals takes place, since the relevant faces of the
prism 140 are exactly orthogonal to the direction of travel of the
optical signals in the guides 144 and 148. The guides 146 and 150
carry no signals at this time. In the second mode of operation,
some form of actuation (e.g. mechanical, electrical or magnetic, as
described in connection with the earlier embodiments) causes the
prism to rotate through 45.degree. to assume the position shown in
FIG. 5(b), whereby refraction now takes place and the signals from
the network are forced to leave by way of the guide 150 and to
re-enter, after passing through the optical element to which the
second connector half (not shown) is connected, the switch through
guide 146, where it passes through the prism once more and leaves
via guide 148.
[0047] Another form of switch is shown in FIG. 6(a). In FIG. 6(a)
four optical guides 160, 162, 164 and 166 are accommodated in an
"X" formation inside the switch body 168, but without touching at
the centre. Situated between guides 160 and 164 on the one hand and
guides 162 and 166 on the other is a reflecting element 170, which
has a reflecting surface on both sides. The reflecting element 170
is attached to an actuating arm 172, which is actuated by any of
the methods heretofore described.
[0048] In operation, in the first mode described earlier the
reflecting element 170 is lifted above the line of intersection of
the signals in the guides, so that network signals pass through
guide 160 and out again through guide 166. In the second mode of
operation, on the other hand, when the optical connector halves
coupled to the guides 162 and 164 are to be brought together so as
to couple the optical element into the network, the arm 172 is
displaced, causing a downward movement of the reflecting element
170, whereupon the signal from the guide 160 is reflected out of
the switch via guide 164 and the return signal in the guide 162 is
reflected out of the switch via guide 166 back to the network.
[0049] Although the optical switching device according to the
invention has so far been described as having particular
application to the retrofitting of optical networks with an optical
network, it may also be used in other applications. One such is an
optical sensor distribution system, where, for example, an optical
temperature sensor could be plugged into a fiber ring as required.
Another application could be an optical power distribution system,
where optical power could be extracted from a ring by attaching to
a connector-switch already inserted in the ring. A third
alternative would be to use the connector-switch of the invention
to allow a transceiver device to be clipped onto a secure
communications ring in, for example, a military network.
[0050] FIG. 7 shows an optical switch-connector device 170 with
receiving means such as that referenced 171 as part of an adapter
casing 182, the receiving means being configured to receive
corresponding connector 172. Connector 172 may be selected by the
person skilled in the art from known alternatives. The receiving
means may be shaped to engage a portion of lever 173 and internal
channels of receiving means 171 may be arranged to guide lever 173
to a locked position as connector 172 is inserted by an operator.
As the connector is placed in an engagement which is sufficient to
allow optical communication between the connector and the connector
switch, the internal channels of the receiving means will allow the
compressed lever to suddenly flex into a locked position--the snap
action. As the lever rises in its locked position, the lever may
act against a transmitting arm 174 which lifts a refractive device
175 from outside the line of the optical transmission to within the
line of the optical transmission between an input port 176 and an
output port 177. This will cause light to refract from port 176 to
port 178 and from port 177 to port 179. Lines 180 and 181 may be
configured and end with appropriate connectors (not illustrated in
the figure) plugged into the end of adapter casing 182.
[0051] As connector 172 is removed from its receiving means 171 a
flexure plate 183 lowers the refractive element 175 out of the
optical path of port 76 and 77 so that conventional traffic may
resume.
[0052] The input ports 176 etc may include collimators of
approximately 1 mm diameter and 7 mm length. The refractive element
may have a thickness of approximately 1 mm and a width of 2 mm.
Other dimensions may of course be selected by the person skilled in
the art as appropriate for particular applications.
[0053] FIG. 8 shows an adapter 184 with receiving means 185 of a
kind which may accommodate a duplex patch cable with a single lever
for activating the refractive element. Internal channels such as
that referenced 186 may be provided in a similar manner as those
discussed above with reference to FIG. 7 to guide and lock a lever
of the appropriate connector. Two optical mating tunnels 187 and
188 are provided for engaging the optical ends of respective
connectors.
[0054] FIG. 9 schematically illustrates a 2 X1 optical switch
generally referenced 189 located on top of an adaptor casing 190
destined to operate with .a single connector 191. As the single
connector is secured in its corresponding receiving means, the snap
action associated with the locking of the connector in position may
lift an arm 192 and its corresponding refractive element 193 in the
optical path of light travelling between collimators 194 and 195.
The effect of the refractive element in its lifted position will be
to refract light from collimator 194 to collimator 196 and on to
connector 191 via the adapter casing 190.
[0055] All the embodiments of FIGS. 7 through 9 may be modified by
the person skilled in the art so that when an operator engages the
connector, switching effectuating means such as arm 192, may be
actuated upon. The switching effectuating means may include
magnetic, electronic and any other appropriate form of triggering
mechanism which occurs when the connector is in an appropriate
optical connection position. The systems may achieve switching
speeds of the order of 10 ms, so that any interruption to the flow
of traffic is minimised and almost done away with entirely.
[0056] FIG. 10 shows a connector 201 which may be of standard
construction and a receiving means 202. Once the connector is mated
to the receiving means optical element 203 may be added to the
network. Switch 204 may be a switch of a standard kind whose
switching is triggered by an external source - key 205. Once the
connector is secured into the receiving means, pin and solenoid
assembly 206 is actuated when the key actuates the switch. If a
standard connector with lever is employed the pin may be selected
to be able to lodge behind the lever to lock the connector in
place.
[0057] FIG. 11 (identical numerical references have been used for
similar components as those of FIG. 10) shows the use of a
micro-switch 207 which is located in series in the circuit.
* * * * *